Method for handover between heterogeneous networks using link trigger signal in multi-interface mobile router

1. A method for a handover between heterogeneous networks including a first network and a second network, using a link trigger signal in a multi-interface mobile router having a first network access interface for accessing the first network and a second network access interface for accessing the second network, the method comprising: generating by the second network access interface a second network link-up trigger signal when the mobile router enters the second network; while the mobile router is located in the first network, maintaining by the mobile router a state of the second network access interface in a sleep state, activating the first network access interface, receiving a first network service through the activated first network access interface, and transmitting the first network service to a subordinate node; when the mobile router senses the generated second network link-up trigger signal while moving to the second network, changing the state of the second network access interface into an active state and performing by the mobile router the handover to the second network; and after performing the handover to the second network, receiving by the mobile router a second network service through the activated second network access interface in the mobile router and transmitting the second network service to the subordinate node, wherein the second network link-up trigger signal is generated by a layer 1 / 2 process of the second network access interface, and wherein the generated second network link-up trigger signal is notified to a mobile IP layer of the mobile router.

2. The method of claim 1 , further comprising: generating by the first network access interface a first network link-down trigger signal when the first network access interface does not receive a signal from the first network; and when the mobile router performing the handover, senses the generated first network link-down trigger signal while moving and entering the second network, changing a state of the first network access interface into the sleep state.

3. The method of claim 2 , wherein the first network link-down trigger signal is generated by evaluating any one of a beacon signal, a radio signal strength, S/N ratio, and a data transmission change rate for the first network access interface in the active state.

4. The method of claim 2 , wherein the first network link-down trigger signal is generated by a layer 1 / 2 process of the first network access interface.

5. The method of claim 4 , wherein the generated first network link-up trigger signal is notified to a mobile IP layer of the mobile router.

6. The method of claim 1 , wherein the first network is a wireless network as a home network, the second network is a satellite network as a foreign network, the first network access interface is a wireless network access interface, and the second network access interface is a satellite network access interface.

7. The method of claim 6 , wherein the mobile router accesses to a base station of the wireless network through the wireless network access interface, and performs, based on a unique IP address as a home address of the mobile router, Internet Protocol (IP) communication with a correspondent node through a home agent.

8. The method of claim 7 , further comprising generating by the satellite network access interface a satellite network link-up trigger signal when the mobile router enters the satellite network, wherein when the generated satellite network link-up trigger signal is sensed, the mobile router performs the handover according to a mobile IP registration procedure for registering with a foreign agent and the home agent through the satellite network access interface, and maintains the IP communication with the correspondent node based on a temporary IP address as a Care-of-Address of the mobile router.

9. The method of claim 8 , further comprising generating by the wireless network access interface a wireless network link-down trigger signal when the wireless network access interface does not receive a signal from the wireless network, wherein when the mobile router senses the generated wireless network link-down trigger signal, the IP communication with the correspondent node is maintained through a tunnel between the foreign agent and the home agent through the satellite network access interface.

10. The method of claim 1 , wherein the first network is a satellite network as a foreign network, the second network is a wireless network as a home network, the first network access interface is a satellite network access interface, and the second network access interface is a wireless network access interface.

11. The method of claim 10 , further comprising generating by the wireless network access interface a wireless network link-up trigger signal when the mobile router enters the wireless network, wherein when the mobile router senses the generated wireless network link-up trigger signal while moving to the wireless network, a mobile IP registration release procedure is performed to release an IP registration from a base station and a home agent through the wireless network access interface.

12. The method of claim 11 , further comprising generating by the satellite network access interface a satellite network link-down trigger signal when the satellite network access interface does not receive a signal from the satellite network, wherein after the mobile IP registration release procedure is performed through the wireless network access interface, the mobile router, when sensing the generated satellite network link-down trigger signal, performs IP communication with a correspondent node through the base station and the home agent.

13. The method of claim 1 , wherein the second network link-up trigger signal is generated by evaluating any one of a beacon signal, radio signal strength, a signal-to-noise ratio (S/N) for the second network access interface in the sleep state, and GPS location information of the mobile router.